Tire-mandrel and method of producing the same



J. R. GAMMET-ER. TIRE MANDREL AND METHOD OF PRODUCING THE SAME. APPLICAIION FILED uovrs. ms.

1,353,158, I Patentedsept.2 l,l920.

/ VE N TOR.-

' UNITED I S A- res E T: 1 FFICE-f- 301m 3." swimmer; or; 1133011,; onto,- 'Assiei oa TO THE-I Bi a. eoonmcntcomramt,

, or NEw YoRK,,-1\pY.., A CORPORATION or new YORK. e

b all f Akron, vin the-county of Summit and Be it, known that-I, JOHN R. GAMMETER, a citizenof theg-jllnit'ed States, residin at tate of Ohio, hayefl'invented .certain new and useful Improvements in Tire-M'andrels and Methods of Producing-the Same, of which the following'is aspecification.

This invention relates to expansible man-,-

drel's.for the manufacture of hollow articles, and particularly pneumatic tire casings. Its object is to provide acore or mandrel of sufficient rigidity to enable the article to be formed thereover, but also capable of being stretched by fluid'pressure' topexpand the formed article and'press it against a mold or similar confining surface, Incidentally I aim to provide a mandrel which may be cheaply manufactured and-may be readily removed from the tire casing-or other hollow article, and the material ofwhich' can be used over again with but small waste and labor.

Specifically, I provide by means of my invention a hollow mandrel or tire-making.

core ofa suitable soft metal such as 1ead.or

lead alloy, and Imayexpand or stretch said -mandrel by fluid pressure inthe process of I making it, in; order to, give it the desired size and contour, and again, desired, for the purpose of expanding-an initially un-, dersized tire casing or :othervul'camzable article a'ndcausing the lattencompletely to fill the. outer mold; during,yulcanization, 'My' invention further. consists in certain details hereinafter described and claimed.-

Of the accompanying drawings, f 1 Figure 1 is a cross-sectional "ew ofa tire mold containing a tire 'casi'n'g' and a lead mandrel embodying my invention.)

Fig, ,2 's a slde elevation ofa helical lead pipe from which the mandrel-is'made.

be 'oined' toform a tubular annulus.

to be expanded and brought to proper size i the mold for the purpose of consol dating and-shape by hydraulicpressureig. 3 is' an elevation showing one turn of the helical pipeeut off and, its endsready to e V e d I be vulcanized it is placed therewith in a tlre align-Mexican AND METHOD or rnonucme r1111 Specification of Letters Patent. Patented. $61 113. 19 20;. Application fiieamvember s, 1916. Serial No. 130,161;

In the drawings, 2, is" a coil" .or- I helm of pipe which may. be produced from melted lead, preferably alloyed with a" small percentage, of t1n, by extrusion through/a die in theordinary way, the. diameter of the helix being approximately that which is desiredfor the unstretched mandrel, vand the sectional diameter of the pipebeing slightly less than that of the sizing and. forming mol'd in which it is to be placed.- If this hehx is then sawed through, on one side along an axialplane,' -it will be divided into broken rings, each one o'f-which is adapted to form an annular mandrel. One of'these broken rings 10 is shown in Fig. 3, and in order to'make -1t endless and' fluid-tight its ends are s0ldered,'welde'd, or otherwise suit-- vided circumferentiallyinto segments which are held together-by endless bolted clampng-rlngsl; The outer periphery of ring 13 1s shghtly'groove'd or hollowed to-form a concave seat 13 for the lead body of the man- 'drel, and the ring has a suitable aperture for the passage of pipe 12. This structure is then assembled between thehalves of a mold 15 whose annular cavity 16' is of the desired shape and size for the mandrelbody. The,.

latter is expanded to fill this cavity byine'an ofhydraulic pressureconducted through a'" pipe 17 which is coupled to the pipe-section 12. On removing the halves of the outer mold 15, the lead -ma 'lrelf 10 together with the boltedsegmental ring 13 to which it is attached, is then ready for formingia tire or .tire carcass.

The,tire casing 18'is builtup -in the usual 'way upon the mandrel, and when rea'dy to m'old 19., preferably having a cavity 20 somewhat larger than the size of the raw. tire in order to permit expansion of the tire within expanded condition, the halves of the outer mold 1'9 are 'removedandthe mandrel can then be removed from the tire by'unbolting 10.-

- mental ring 13 and pulling the leadcore 10".

. out of the casing. As the core is thin walled the clamping rings 14, taking apart the segand easily bent, it may be hooked out of the 'casingwith a suitable tool. -The lead can then beremelted and-used over. again.

'Someof theadvantages of my invention -may be realizedwithout.expandingthe core within the tire, the latter-being made, to the full size of the mold cavity, or cured in open steam by the wrapped-tread method, or otherwise cured. It will be further understood that various modifications may be madewithin the scope of or in the manner of use o f-the-invention. For example, the

lead mandrel. could be expanded by gas from a suitable powder which might be placed in 'a 'smallflask detachably connected to the "pipe-section 12,011 the order of the app ratus' described'inmy Patent No. 1,200,603.

The term lead, as used in the claims, in-

new

cludes a lead 51103 which willremain solid at vulcanizing temperatures.

I claim: 1. A fluid-tight, hollow, stretchable, metallic mandrel. r

2. A relatively thin-walled, fluid-tight,

to remain solid at vulcanizing temperatures. A tire-making mandrel comprising a fluid-tight, hollow, lead annulus provided hollow, lead tire-making mandrel adapted with aninletfor introducing an expanding fluid.

4. A tire-making inner rigid metallic. ring adapted to fit between the halves of a tire mold, and an outer annular, hollow, lead mandrel-body thereon.

.5. A tire-making mandrel comprisingla rigid metallic tongue-ring divided circumferentially into segments, and an expansible, hollow, lead mandrel-body seated thereon.

6. A tire-makiing mandrel comprising an mandrel comprising an inner rigid metallic ring adapted to fitbetween the halves of a tire; mold, and an outer,

annular, hollow, lead mandrel-body thereon,

provided with a fluid inlet-pipe extending through said ring.

In testimony whereof I have hereunto set my hand this 28 da of October, 1916.. JOI IN R. GAMMETER. 

